Aromatic amine derivative and organic electroluminescent device using the same

ABSTRACT

Provided are: an aromatic amine derivative in which a terminal substituent such as a dibenzofuran ring or a dibenzothiophene ring is bonded to a nitrogen atom directly or through an arylene group or the like; an organic electroluminescence device including an organic thin film layer formed of one or more layers including a light emitting layer and interposed between a cathode and an anode in which a layer of the organic thin film layer contains the aromatic amine derivative by itself or as a component of a mixture, and the device has a long lifetime and high luminous efficiency; and an aromatic amine derivative for realizing the device.

TECHNICAL FIELD

The present invention relates to an aromatic amine derivative and anorganic electroluminescence device using the same, in particular, anorganic electroluminescence device having a long lifetime and highluminous efficiency, and an aromatic amine derivative for realizing thedevice.

BACKGROUND ART

A large number of organic electroluminescence (EL) devices each using anorganic substance have been developed because of their potential to findapplications in solid light emission type, inexpensive, large-area,full-color display devices. In general, an organic EL device isconstituted of a light emitting layer and a pair of opposing electrodesbetween which the layer is interposed. Light emission is the phenomenonin which when an electric field is applied between both the electrodes,an electron is injected from a cathode side and a hole is injected froman anode side, and further, the electron recombines with the hole in thelight emitting layer to produce an excited state, and energy generatedupon return of the excited state to a ground state is emitted as light.

A conventional organic EL device was driven at a voltage higher than thevoltage at which an inorganic light emitting diode is driven, and hademission luminance and luminous efficiency lower than those of thediode. In addition, the properties of the device deterioratedremarkably, so the device has not been put into practical use. A recentorganic EL device has been gradually improved, but actually,additionally high luminous efficiency and an additionally long lifetimeof the device are still requested.

For example, a technology involving the use of a single monoanthracenecompound as an organic light emitting material has been disclosed(Patent Document 1). However, the technology is not practical becauseof, for example, the following reasons. That is, a luminance of only1650 cd/m² is obtained at a current density of 165 mA/cm², andefficiency is 1 cd/A, which is an extremely low value. In addition, atechnology involving the use of a single bisanthracene compound as anorganic light emitting material has been disclosed (Patent Document 2).However, an improvement for putting the technology into practical usehas been requested because efficiency is as low as about 1 to 3 cd/A.Meanwhile, a long-lifetime organic EL device using a distyryl compoundas an organic light emitting material and styrylamine or the like addedto the compound has been proposed (Patent Document 3). However, anadditional improvement of the device has been requested because thedevice does not have a sufficient lifetime.

In addition, a technology involving the use of a monoanthracene orbisanthracene compound and a distyryl compound in an organic lightemitting medium layer has been disclosed (Patent Document 4). In suchtechnology, however, an emission spectrum shifts to longer wavelengthsowing to the conjugate structure of the styryl compound, and hence acolor purity deteriorates.

In addition, Patent Document 5 discloses an invention in which anaromatic amine derivative having an arylene group at its center and adibenzofuran ring bonded to a nitrogen atom is used as a holetransporting material, and Patent Document 6 discloses an invention inwhich an aromatic amine derivative having a dibenzofuran ring,dibenzothiophene ring, benzofuran ring, benzothiophene ring, or the likebonded to a nitrogen atom through an arylene group is used as a holetransporting material. However, there are no cases where the derivativesare used as light emitting materials.

Patent Document 1: JP 11-3782 A

Patent Document 2: JP 08-12600 A

Patent Document 3: WO 94/006157 A1

Patent Document 4: JP 2001-284050 A

Patent Document 5: JP 3508984 B2

Patent Document 6: WO 07/125714 A1

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The present invention has been made to solve the above-mentionedproblems, and an object of the present invention is to provide anorganic EL device having a long lifetime and high luminous efficiency,and an aromatic amine derivative for realizing the device.

Means for Solving the Problems

The inventors of the present invention have made extensive studies witha view to developing an aromatic amine derivative having the preferredproperties and an organic EL device using the derivative. As a result,the inventors have achieved high luminous efficiency and a lengthenedlifetime by finding the following fact. That is, when an aromatic aminederivative having a fused aromatic hydrocarbon group on its centralskeleton where a rigid, sterically bulky terminal substituent such as adibenzofuran ring or a dibenzothiophene ring is bonded to a nitrogenatom directly or through an arylene group or the like is usedparticularly as a light emitting material, concentration quenchinghardly occurs through an influence of the terminal substituent. Thepresent invention has been completed on the basis of such finding.

That is, the present invention provides an aromatic amine derivativerepresented by the following general formula (1):

Aromatic amine derivative represented by the following general formula(1):

where Ar₀ represents a substituted or unsubstituted, divalent fusedaromatic hydrocarbon group having 10 to 50 ring-forming carbon atoms,and Ar₁ to Ar₄ each independently represent a substituted orunsubstituted aryl group having 6 to 50 ring-forming carbon atoms, asubstituted or unsubstituted alkyl group having 1 to 50 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 50ring-forming carbon atoms, a substituted or unsubstituted aralkyl grouphaving 7 to 50 ring-forming carbon atoms, or a substituted orunsubstituted heterocyclic group having 5 to 50 ring-forming atoms,provided that one or more of Ar₁ to Ar₄ each represent a grouprepresented by the following general formula (2) or (3):

where n represents an integer of 0 to 3, m represents an integer of 0 to5, 1 represents an integer of 0 to 7, X represents oxygen (O), sulfur(S), or selenium (Se), Ar represents a substituted or unsubstitutedarylene group having 6 to 60 ring-forming carbon atoms, R represents asubstituted or unsubstituted aryl group having 6 to 60 ring-formingcarbon atoms, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, an amino group, a substituted or unsubstituted alkoxygroup having 1 to 50 carbon atoms, a substituted or unsubstitutedaryloxy group having 7 to 50 ring-forming carbon atoms, a substituted orunsubstituted arylthio group having 6 to 50 ring-forming atoms, asubstituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbonatoms, a halogen atom, a cyano group, a nitro group, a hydroxyl group, asilyl group, or a carboxyl group, when n, m, or 1 represents 2 or more,multiple Ar's or multiple R's may be identical to or different from eachother, and when multiple R's are present, the multiple R's may be bondedto each other to form a saturated or unsaturated, five- or six-memberedcyclic structure that may be substituted, provided that: when n=0, afive-membered ring portion including X in the general formula (2) isfree from being directly bonded to N bonded to Ar₀; and in the generalformula (3), a case where (R)₁ and (Ar)_(n) are bonded to afive-membered ring portion including X is excluded.

In addition, the present invention provides an organic EL deviceincluding an organic thin film layer formed of one or more layersincluding at least alight emitting layer and interposed between acathode and an anode, in which at least one layer of the organic thinfilm layer contains the aromatic amine derivative by itself or as acomponent of a mixture.

Effects of the Invention

The organic EL device using the aromatic amine derivative of the presentinvention has high luminous efficiency, hardly deteriorates even whenused for a long time period, and has a long lifetime.

BEST MODE FOR CARRYING OUT THE INVENTION

An aromatic amine derivative of the present invention is a compoundrepresented by the following general formula (1).

In the general formula (1), Ar₀ represents a substituted orunsubstituted, divalent fused aromatic hydrocarbon group having 10 to 50ring-forming carbon atoms.

Examples of the fused aromatic hydrocarbon group represented by Ar₀include a naphthylene group, an anthracenylene group, a phenanthrylenegroup, a chrysenylene group, a pyrenylene group, a benzoanthracenylenegroup, a fluoranthenylene group, a benzofluoranthenylene group, aperylenylene group, a coronenylene group, a picenylene group, adiphenylanthracenylene group, a fluorenylene group, a triphenylylenegroup, a rubicenylene group, a phenylanthracenylene group, abisanthracenylene group, a dianthracenylbenzynylene group, and adibenzoanthracenylene group. Of those, a naphthylene group, ananthracenylene group, a phenanthrylene group, a chrysenylene group, apyrenylene group, and a benzoanthracenylene group are preferred.

In addition, it is preferred that —NAr₁Ar₂ and —NAr₃Ar₄ be bonded to 2-and 6-positions of the naphthylene group, respectively, —NAr₁Ar₂ and—NAr₃Ar₄ be bonded to 1- and 4-positions of the naphthylene group,respectively, —NAr₁Ar₂ and —NAr₃Ar₄ be bonded to 9- and 10-positions ofthe anthracenylene group, respectively, —NAr₁Ar₂ and —NAr₃Ar₄ be bondedto 2- and 6-positions of the anthracenylene group, respectively,—NAr₁Ar₂ and —NAr₃Ar₄ be bonded to 2- and 7-positions of thephenanthrylene group, respectively, —NAr₁Ar₂ and —NAr₃Ar₄ be bonded to6- and 12-positions of the chrysenylene group, respectively, —NAr₁Ar₂and —NAr₃Ar₄ be bonded to 1 and 6-positions of the pyrenylene group,respectively, —NAr₁Ar₂ and —NAr₃Ar₄ be bonded to 2- and 7-positions ofthe pyrenylene group, respectively, —NAr₁Ar₂ and —NAr₃Ar₄ be bonded to7- and 12-positions of the benzoanthracenylene group, respectively, or—NAr₁Ar₂ and —NAr₃Ar₄ be bonded to 7- and 12-positions of thebenzofluoranthenylene group, respectively.

In the general formula (1), Ar₁ to Ar₄ each independently represent asubstituted or unsubstituted aryl group having 6 to 50 ring-formingcarbon atoms (or preferably 6 to 20 ring-forming carbon atoms), asubstituted or unsubstituted alkyl group having 1 to 50 carbon atoms (orpreferably 1 to 20 carbon atoms), a substituted or unsubstitutedcycloalkyl group having 3 to 50 ring-forming carbon atoms (or preferably5 to 12 ring-forming carbon atoms), a substituted or unsubstitutedaralkyl group having 7 to 50 ring-forming carbon atoms (or preferably 7to 20 ring-forming carbon atoms), or a substituted or unsubstitutedheterocyclic group having 5 to 50 ring-forming atoms (or preferably 5 to20 ring-forming atoms).

Examples of the aryl group represented by any one of Ar₁ to Ar₄ includea phenyl group, a 2-methylphenyl group, a 3-methylphenyl group, a4-methylphenyl group, a 4-ethylphenyl group, a biphenyl group, a4-methylbiphenyl group, a 4-ethylbiphenyl group, a 4-cyclohexylbiphenylgroup, a terphenyl group, a 3,5-dichlorophenyl group, a naphthyl group,a 5-methylnaphthyl group, an anthryl group, a pyrenyl group, a chrysenylgroup, a fluoranthenyl group, and a perylenyl group.

Examples of the alkyl group represented by any one of Ar₁ to Ar₁ includea methyl group, an ethyl group, a propyl group, an isopropyl group, abutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, ahexyl group, a heptyl group, an octyl group, a stearyl group, a2-phenylisopropyl group, a trichloromethyl group, a trifluoromethylgroup, a benzyl group, an α-phenoxybenzyl group, an α,α-dimethylbenzylgroup, an α,α-methylphenylbenzyl group, an α,α-ditrifluoromethylbenzylgroup, a triphenylmethyl group, and an α-benzyloxybenzyl group.

Examples of the cycloalkyl group represented by any one of Ar₁ to Ar₄include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononylgroup, a bicycloheptyl group, a bicyclooctyl group, a tricycloheptylgroup, and an adamantyl group. Of those, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a bicycloheptyl group, abicyclooctyl group, and an adamantyl group are preferred.

Examples of the aralkyl group represented by any one of Ar₁ to Ar₄include a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group, a1-phenylisopropyl group, a 2-phenylisopropyl group, a phenyl-t-butylgroup, an α-naphthylmethyl group, a 1-α-naphthylethyl group, a2-α-naphthylethyl group, a 1-α-naphthylisopropyl group, a2-α-naphthylisopropyl group, a β-naphthylmethyl group, a1-β-naphthylethyl group, a 2-β-naphthylethyl group, a1-β-naphthylisopropyl group, a 2-β-naphthylisopropyl group, a1-pyrrolylmethyl group, a 2-(1-pyrrolyl)ethyl group, a p-methylbenzylgroup, an m-methylbenzyl group, an o-methylbenzyl group, ap-chlorobenzyl group, an m-chlorobenzyl group, an o-chlorobenzyl group,a p-bromobenzyl group, an m-bromobenzyl group, an o-bromobenzyl group, ap-iodobenzyl group, an m-iodobenzyl group, an o-iodobenzyl group, ap-hydroxybenzyl group, an m-hydroxybenzyl group, an o-hydroxybenzylgroup, a p-aminobenzyl group, an m-aminobenzyl group, an o-aminobenzylgroup, a p-nitrobenzyl group, an m-nitrobenzyl group, an o-nitrobenzylgroup, a p-cyanobenzyl group, an m-cyanobenzyl group, an o-cyanobenzylgroup, a 1-hydroxy-2-phenylisopropyl group, and a1-chloro-2-phenylisopropyl group.

Examples of the heterocyclic group represented by any one of Ar₁ to Ar₄include residues of imidazole, benzimidazole, pyrrole, furan, thiophene,oxadiazoline, indoline, carbazole, pyridine, quinoline, isoquinoline,benzoquinone, pyralozine, imidazolidine, and piperidine.

It should be noted that one or more of Ar₁ to Ar₄ in the general formula(1) each represent a group represented by the following general formula(2) or (3).

In the general formula (1), Ar₁ and Ar₃ each preferably represent agroup represented by the general formula (2) or (3), or all of Ar₁ toAr₄ each more preferably represent a group represented by the generalformula (2) or (3).

In addition, one or more of Ar₁ to Ar₄ in the general formula (1) eachpreferably represent a group represented by the general formula (3).

In the general formulae (2) and (3), n represents an integer of 0 to 3(or preferably 0), m represents an integer of 0 to 5 (or preferably 0 to2), and 1 represents an integer of 0 to 7 (or preferably 0 to 4).

In addition, when n, m, or 1 represents 2 or more, multiple Ar's ormultiple R's may be identical to or different from each other.

It should be noted that, when n=0 in the general formula (2), afive-membered ring portion including X is not directly bonded to Nbonded to Ar₀. In addition, in the general formula (3), the case where(R)₁ and (Ar)_(n) are bonded to a five-membered ring portion including Xis excluded.

In each of the general formulae (2) and (3), X represents oxygen (O),sulfur (S), or selenium (Se), or preferably an oxygen atom or a sulfuratom.

In addition, when n in the general formula (3) represents 0, it ispreferred that X represent an oxygen atom or a sulfur atom, and abonding position be present at a 2- or 4-position (or more preferablythe 2-position) of a fused ring including X.

In each of the general formulae (2) and (3), Ar represents a substitutedor unsubstituted arylene group having 6 to 60 ring-forming carbon atoms(or preferably 6 to 20 ring-forming carbon atoms), and examples of thearylene group include groups obtained by making the specific examples ofthe aryl group described for Ar₁ to Ar₄ divalent.

In each of the general formulae (2) and (3), R represents a substitutedor unsubstituted aryl group having 6 to 60 ring-forming carbon atoms (orpreferably 6 to 20 ring-forming carbon atoms), a substituted orunsubstituted alkyl group having 1 to 50 carbon atoms (or preferably 1to 20 carbon atoms), an amino group, a substituted or unsubstitutedalkoxy group having 1 to 50 carbon atoms (or preferably 1 to 6 carbonatoms), a substituted or unsubstituted aryloxy group having 6 to 50ring-forming carbon atoms (or preferably 6 to 18 ring-forming carbonatoms), a substituted or unsubstituted arylthio group having 6 to 50ring-forming atoms (or preferably 6 to 18 ring-forming carbon atoms), asubstituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbonatoms, a halogen atom, a cyano group, a nitro group, a hydroxyl group, asilyl group, or a carboxyl group. In addition, when multiple R's arepresent, the multiple R's may be bonded to each other to form asaturated or unsaturated, five- or six-membered cyclic structure thatmay be substituted.

In each of the general formulae (2) and (3), R preferably represents asilyl group.

Specific examples of the aryl group and the alkyl group each representedby R include the same examples as those of the aryl group and the alkylgroup described for Ar₁ to Ar₄.

In addition, examples of the alkoxy group represented by R include amethoxy group, an ethoxy group, a propoxy group, an isopropoxy group, abutoxy group, an isobutoxy group, an sec-butoxy group, a tert-butoxygroup, various pentyloxy groups, and various hexyloxy groups.

The alkoxycarbonyl group represented by R is represented as —COOZ, andexamples of Z include the same examples as those of the alkyl groupdescribed for Ar₁ to Ar₄.

The aryloxy group and the arylthio group each represented by R arerepresented as —OY and —SY, respectively, and examples of Y include thesame examples as those of the aryl group described for Ar₁ to Ar₄.

In the general formulae (2) and (3), m and 1 each preferably represent0.

It should be noted that the number of carbon atoms or atoms of eachgroup of each of the above-mentioned general formulae is a numberexcluding that of a substituent. In addition, the number of carbon atomsof an aralkyl group is the number of carbon atoms of an aryl portion.

An arbitrary substituent in the “substituted or unsubstituted . . .group” in each of the above-mentioned general formulae is, for example,a substituted or unsubstituted aryl group having 6 to 50 ring-formingcarbon atoms, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50carbon atoms, a substituted or unsubstituted aralkyl group having 7 to50 ring-forming carbon atoms, a substituted or unsubstituted aryloxygroup having 6 to 50 ring-forming carbon atoms, a substituted orunsubstituted arylthio group having 6 to 50 ring-forming carbon atoms, asubstituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbonatoms, an amino group, a halogen atom, a cyano group, a nitro group, ahydroxyl group, or a carboxyl group.

Of those, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl grouphaving 5 to 7 carbon atoms, and an alkoxy group having 1 to 10 carbonatoms are preferred, an alkyl group having 1 to 6 carbon atoms and acycloalkyl group having 5 to 7 carbon atoms are more preferred, and amethyl group, an ethyl group, an n-propyl group, an isopropyl group, ann-butyl group, an sec-butyl group; a tert-butyl group, an n-pentylgroup, an n-hexyl group, a cyclopentyl group, and a cyclohexyl group areparticularly preferred.

Specific examples of the aromatic amine derivative represented by thegeneral formula (1) of the present invention are shown below. However,the present invention is not limited to these exemplified compounds.

TABLE 1 No Ar₀ Ar₁ Ar₂ Ar₃ Ar₄ D-1

D-2

D-3

D-4

D-5

D-6

D-7

D -8

D-9

D-10

TABLE 2 No Ar₀ Ar₁ Ar₂ Ar₃ A_(r4) D-11

D-12

D-13

D-14

D-15

D-16

D-17

D-18

D-19

D-20

TABLE 3 No Ar₀ Ar₁ Ar₂ Ar₃ Ar₄ D-21

D-22

D-23

D-24

D-25

D-26

D-27

D-28

D-29

D-30

TABLE 4 No Ar₀ Ar₁ Ar₂ Ar₃ Ar₄ D-31

D-32

D-33

D-34

D-35

D-36

D-37

D-38

D-39

D-40

TABLE 5 No Ar₀ Ar₁ Ar₂ Ar₃ Ar₄ D-41

D-42

D-43

D-44

D-45

D-46

D-47

D-48

D-49

D-50

TABLE 6 No Ar₀ Ar₁ Ar₂ Ar₃ Ar₄ D-51

D-52

D-53

D-54

D-55

D-56

D-57

D-58

D-59

D-60

TABLE 7 No Ar₀ Ar₁ Ar₂ Ar₃ Ar₄ D-61

D-62

D-63

D-64

D-65

D-66

D-67

D-68

D-69

D-70

Next, a production method of the aromatic amine derivative of thepresent invention is described.

A method of producing the aromatic amine derivative represented by thegeneral formula (1) of the present invention is not particularlylimited, and it is sufficient that the aromatic amine derivative beproduced by a known method. For example, the aromatic amine derivativeis produced by aminating 6,12-dibromochrysene obtained by the methoddescribed in Rev. Roum. Chim., 34, p. 1907 (1989) (M. D. Bancia et al.)with a diarylamine.

The aromatic amine derivative of the present invention is suitably usedas a material for an organic EL device, and is particularly preferablyused as a light emitting material. The aromatic amine derivative issuitably used as a blue light emitting material or a green lightemitting material.

In addition, the aromatic amine derivative of the present invention issuitably used also as a doping material for an organic EL device.

An organic EL device of the present invention is a device in which anorganic thin film layer formed of one or more layers is formed betweenan anode and a cathode. When the device is of a one-layer type, a lightemitting layer is provided between the anode and the cathode. The lightemitting layer contains a light emitting material, and may contain ahole injecting material or an electron injecting material in addition tothe light emitting material in order that a hole injected from the anodeor an electron injected from the cathode may be transported to the lightemitting material. The aromatic amine derivative of the presentinvention may be used as a light emitting material or doping material ina light emitting layer because the aromatic amine derivative has a highlight emitting characteristic, an excellent hole injectingcharacteristic, an excellent hole transporting characteristic, anexcellent electron injecting characteristic, and an excellent electrontransporting characteristic.

In the organic EL device of the present invention, the light emittinglayer preferably contains the aromatic amine derivative, of the presentinvention, and the content is preferably 0.1 to 20 mass %, or morepreferably 1 to 10 mass % in ordinary cases. In addition, the lightemitting layer may be formed only of the aromatic amine derivative ofthe present invention because the aromatic amine derivative bringstogether extremely high fluorescent quantum efficiency, a high holetransporting ability, and a high electron transporting ability, andenables the formation of a uniform thin film.

In addition, the organic EL device of the present invention ispreferably an organic EL device having an organic thin film layer formedof two or more layers including at least a light emitting layer andinterposed between a cathode and an anode in which an organic layermainly formed of the aromatic amine derivative of the present inventionis placed between the anode and the light emitting layer. Examples ofthe organic layer include a hole injecting layer and a hole transportinglayer.

Further, when the aromatic amine derivative of the present invention iscontained as a doping material, it is preferred to contain at least onekind selected from an anthracene derivative represented by the followinggeneral formula (i) and a pyrene derivative represented by the followinggeneral formula (ii).

In the general formula (i), A₁ and A₂ each independently represent agroup derived from a substituted or unsubstituted aromatic ring having 6to 20 ring-forming carbon atoms. The aromatic ring may be substitutedwith one or two or more substituents. The substituent for the aromaticring is selected from, a substituted or unsubstituted aryl group having6 to 50 carbon atoms, a substituted or unsubstituted alkyl group having1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl grouphaving 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 50 carbon atoms, a substituted or unsubstituted aralkylgroup (the aryl portion having 6 to 50 carbon atoms and the alkylportion having 1 to 5 carbon atoms), a substituted or unsubstitutedaryloxy group having 6 to 50 carbon atoms, a substituted orunsubstituted arylthio group having 6 to 50 carbon atoms, a substitutedor unsubstituted alkoxycarbonyl group (the alkoxy portion having 1 to 50carbon atoms), a substituted or unsubstituted silyl group, a carboxylgroup, a halogen atom, a cyano group, a nitro group, and a hydroxylgroup. Specific examples of the groups represented in R⁵ to R¹² aredescribed below. When the aromatic ring is substituted with two or moresubstituents, the substituents may be identical to or different fromeach other. Substituents adjacent to each other may be bonded to eachother to form a saturated or unsaturated cyclic structure. A₁ and A₂ arepreferably different from each other. In addition, at least one of A₁and A₂ preferably represents a substituent having a substituted orunsubstituted fused ring group having 10 to 30 carbon atoms, or morepreferably represents a substituent having a substituted orunsubstituted naphthyl group.

Examples of the substituted or unsubstituted group derived from anaromatic ring having 6 to 20 ring-forming carbon atoms represented byany one of A₁ and A₂ include a phenyl group, al-naphthyl group, a2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthrylgroup, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthrylgroup, a 4-phenanthryl group, a 9-phenanthryl group, a 1-naphthacenylgroup, a 2-naphthacenyl group, a 9-naphthacenyl group, a 1-pyrenylgroup, a 2-pyrenyl group, a 4-pyrenyl group, a 2-biphenylyl group, a3-biphenylyl group, a 4-biphenylyl group, a p-terphenyl-4-yl group, ap-terphenyl-3-yl group, a p-terphenyl-2-yl group, an m-terphenyl-4-ylgroup, an m-terphenyl-3-yl group, an m-terphenyl-2-yl group, an o-tolylgroup, an m-tolyl group, a p-tolyl group, a p-t-butylphenyl group, ap-(2-phenylpropyl)phenyl group, a 3-methyl-2-naphthyl group, a4-methyl-1-naphthyl group, a 4-methyl-1-anthryl group, a4′-methylbiphenylyl group, and a 4″-t-butyl-p-terphenyl-4-yl group. Thegroup is preferably a group derived from a substituted or unsubstitutedaromatic ring having 10 to 14 ring-forming carbon atoms, or particularlypreferably a 1-naphthyl group, a 2-naphthyl group, or a 9-phenanthrylgroup.

R₁ to R₈ each independently represent a group selected from a hydrogenatom, a substituted or unsubstituted aryl group having 6 to 50ring-forming carbon atoms, a substituted or unsubstituted heteroarylgroup having 4 to 50 ring-forming atoms, a substituted or unsubstitutedalkyl group having 1 to 50 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 50 ring-forming carbon atoms, a substitutedor unsubstituted alkoxy group having 1 to 50 carbon atoms, a substitutedor unsubstituted aralkyl group having 7 to 50 ring-forming carbon atoms,a substituted or unsubstituted aryloxy group having 6 to 50 ring-formingcarbon atoms, a substituted or unsubstituted arylthio group having 6 to50 ring-forming carbon atoms, a substituted or unsubstitutedalkoxycarbonyl group having 1 to 50 carbon atoms, a substituted orunsubstituted silyl group, a carboxyl group, a halogen atom, a cyanogroup, a nitro group, and a hydroxyl group.

Examples of the substituted or unsubstituted aryl group having 6 to 50ring-forming carbon atoms represented by any one of R₁ to R₈ include aphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group,a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, a9-phenanthryl group, a 1-naphthacenyl group, a 2-naphthacenyl group, a9-naphthacenyl group, a 1-pyrenyl group, a 2-pyrenyl group, a 4-pyrenylgroup, a 2-biphenylyl group, a 3-biphenylyl group, a 4-biphenylyl group,a p-terphenyl-4-yl group, a p-terphenyl-3-yl group, a p-terphenyl-2-ylgroup, an m-terphenyl-4-yl group, an m-terphenyl-3-yl group, anm-terphenyl-2-yl group, an o-tolyl group, an m-tolyl group, a p-tolylgroup, a p-t-butylphenyl group, a p-(2-phenylpropyl)phenyl group, a3-methyl-2-naphthyl group, a 4-methyl-1-naphthyl group, a4-methyl-1-anthryl group, a 4′-methylbiphenylyl group, and a4″-t-butyl-p-terphenyl-4-yl group.

Examples of the substituted or unsubstituted heteroaryl group having 4to 50 ring-forming atoms represented by any one of R₁ to Re include a1-pyrrolyl group, a 2-pyrrolyl group, a 3-pyrrolyl group, a pyrazinylgroup, a 2-pyridinyl group, a 3-pyridinyl group, a 4-pyridinyl group, a1-indolyl group, a 2-indolyl group, a 3-indolyl group, a 4-indolylgroup, a 5-indolyl group, a 6-indolyl group, a 7-indolyl group, a1-isoindolyl group, a 2-isoindolyl group, a 3-isoindolyl group, a4-isoindolyl group, a 5-isoindolyl group, a 6-isoindolyl group, a7-isoindolyl group, a 2-furyl group, a 3-furyl group, a 2-benzofuranylgroup, a 3-benzofuranyl group, a 4-benzofuranyl group, a 5-benzofuranylgroup, a 6-benzofuranyl group, a 7-benzofuranyl group, a1-isobenzofuranyl group, a 3-isobenzofuranyl group, a 4-isobenzofuranylgroup, a 5-isobenzofuranyl group, a 6-isobenzofuranyl group, a7-isobenzofuranyl group, a quinolyl group, a 3-quinolyl group, a4-quinolyl group, a 5-quinolyl group, a 6-quinolyl group, a 7-quinolylgroup, an 8-quinolyl group, a 1-isoquinolyl group, a 3-isoquinolylgroup, a 4-isoquinolyl group, a 5-isoquinolyl group, a 6-isoquinolylgroup, a 7-isoquinolyl group, an 8-isoquinolyl group, a 2-quinoxalinylgroup, a 5-quinoxalinyl group, a 6-quinoxalinyl group, a 1-carbazolylgroup, a 2-carbazolyl group, a 3-carbazolyl group, a 4-carbazolyl group,a 9-carbazolyl group, a 1-phenanthridinyl group, a 2-phenanthridinylgroup, a 3-phenanthridinyl group, a 4-phenanthridinyl group, a6-phenanthridinyl group, a 7-phenanthridinyl group, an 8-phenanthridinylgroup, a 9-phenanthridinyl group, a 10-phenanthridinyl group, a1-acridinyl group, a 2-acridinyl group, a 3-acridinyl group, a4-acridinyl group, a 9-acridinyl group, a 1,7-phenanthrolin-2-yl group,a 1,7-phenanthrolin-3-yl group, a 1,7-phenanthrolin-4-yl group, a1,7-phenanthrolin-5-yl group, a 1,7-phenanthrolin-6-yl group, a1,7-phenanthrolin-8-yl group, a 1,7-phenanthrolin-9-yl group, a1,7-phenanthrolin-10-yl group, a 1,8-phenanthrolin-2-yl group, a1,8-phenanthrolin-3-yl group, a 1,8-phenanthrolin-4-yl group, a1,8-phenanthrolin-5-yl group, a 1,8-phenanthrolin-6-yl group, a1,8-phenanthrolin-7-yl group, a 1,8-phenanthrolin-9-yl group, a1,8-phenanthrolin-10-yl group, a 1,9-phenanthrolin-2-yl group, a1,9-phenanthrolin-3-yl group, a 1,9-phenanthrolin-4-yl group, a1,9-phenanthrolin-5-yl group, a 1,9-phenanthrolin-6-yl group, a1,9-phenanthrolin-7-yl group, a 1,9-phenanthrolin-8-yl group, a1,9-phenanthrolin-10-yl group, a 1,10-phenanthrolin-2-yl group, a1,10-phenanthrolin-3-yl group, a 1,10-phenanthrolin-4-yl group, a1,10-phenanthrolin-5-yl group, a 2,9-phenanthrolin-1-yl group, a2,9-phenanthrolin-3-yl group, a 2,9-phenanthrolin-4-yl group, a2,9-phenanthrolin-5-yl group, a 2,9-phenanthrolin-6-yl group, a2,9-phenanthrolin-7-yl group, a 2,9-phenanthrolin-8-yl group, a2,9-phenanthrolin-10-yl group, a 2,8-phenanthrolin-1-yl group, a2,8-phenanthrolin-3-yl group, a 2,8-phenanthrolin-4-yl group, a2,8-phenanthrolin-5-yl group, a 2,8-phenanthrolin-6-yl group, a2,8-phenanthrolin-7-yl group, a 2,8-phenanthrolin-9-yl group, a2,8-phenanthrolin-10-yl group, a 2,7-phenanthrolin-1-yl group, a2,7-phenanthrolin-3-yl group, a 2,7-phenanthrolin-4-yl group, a2,7-phenanthrolin-5-yl group, a 2,7-phenanthrolin-6-yl group, a2,7-phenanthrolin-8-yl group, a 2,7-phenanthrolin-9-yl group, a2,7-phenanthrolin-10-yl group, a 1-phenazinyl group, a 2-phenazinylgroup, a 1-phenothiazinyl group, a 2-phenothiazinyl group, a3-phenothiazinyl group, a 4-phenothiazinyl group, a 10-phenothiazinylgroup, a 1-phenoxazinyl group, a 2-phenoxazinyl group, a 3-phenoxazinylgroup, a 4-phenoxazinyl group, a 10-phenoxazinyl group, a 2-oxazolylgroup, a 4-oxazolyl group, a 5-oxazolyl group, a 2-oxadiazolyl group, a5-oxadiazolyl group, a 3-furazanyl group, a 2-thienyl group, a 3-thienylgroup, a 2-methylpyrrol-1-yl group, a 2-methylpyrrol-3-yl group, a2-methylpyrrol-4-yl group, a 2-methylpyrrol-5-yl group, a3-methylpyrrol-1-yl group, a 3-methylpyrrol-2-yl group, a3-methylpyrrol-4-yl group, a 3-methylpyrrol-5-yl group, a2-t-butylpyrrol-4-yl group, a 3-(2-phenylpropyl)pyrrol-1-yl group, a2-methyl-1-indolyl group, a 4-methyl-1-indolyl group, a2-methyl-3-indolyl group, a 9-methyl-3-indolyl group, a2-t-butyl-1-indolyl group, a 4-t-butyl-1-indolyl group, a2-t-butyl-3-indolyl group, and a 4-t-butyl-3-indolyl group.

Examples of the substituted or unsubstituted alkyl group having 1 to 50carbon atoms represented by any one of R₁ to R₈ include a methyl group,an ethyl group, a propyl group, an isopropyl group, an n-butyl group, ans-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, ann-hexyl group, an n-heptyl group, an n-octyl group, a hydroxymethylgroup, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a2-hydroxyisobutyl group, a 1,2-dihydroxyethyl group, a1,3-dihydroxyisopropyl group, a 2,3-dihydroxy-t-butyl group, a1,2,3-trihydroxypropyl group, a chloromethyl group, a 1-chloroethylgroup, a 2-chloroethyl group, a 2-chloroisobutyl group, a1,2-dichloroethyl group, a 1,3-dichloroisopropyl group, a2,3-dichloro-t-butyl group, a 1,2,3-trichloropropyl group, a bromomethylgroup, a 1-bromoethyl group, a 2-bromoethyl group, a 2-bromoisobutylgroup, a 1,2-dibromoethyl group, a 1,3-dibromoisopropyl group, a2,3-dibromo-t-butyl group, a 1,2,3-tribromopropyl group, an iodomethylgroup, a 1-iodoethyl group, a 2-iodoethyl group, a 2-iodoisobutyl group,a 1,2-diiodoethyl group, a 1,3-diiodoisopropyl group, a2,3-diiodo-t-butyl group, a 1,2,3-triiodopropyl group, an aminomethylgroup, a 1-aminoethyl group, a 2-aminoethyl group, a 2-aminoisobutylgroup, a 1,2-diaminoethyl group, a 1,3-diaminoisopropyl group, a2,3-diamino-t-butyl group, a 1,2,3-triaminopropyl group, a cyanomethylgroup, a 1-cyanoethyl group, a 2-cyanoethyl group, a 2-cyanoisobutylgroup, a 1,2-dicyanoethyl group, a 1,3-dicyanoisopropyl group, a2,3-dicyano-t-butyl group, a 1,2,3-tricyanopropyl group, a nitromethylgroup, a 1-nitroethyl group, a 2-nitroethyl group, a 2-nitroisobutylgroup, a 1,2-dinitroethyl group, a 1,3-dinitroisopropyl group, a2,3-dinitro-t-butyl group, and a 1,2,3-trinitropropyl group.

Examples of the substituted or unsubstituted cycloalkyl group having 3to 50 ring-forming carbon atoms represented by any one of R₁ to R₈ or asthe substituent on the aromatic ring include a cyclopropyl group, acyclobutyl group, a cyclopentyl group, a cyclohexyl group, a4-methylcyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a1-norbornyl group, and a 2-norbornyl group.

The substituted or unsubstituted alkoxy group having 1 to 50 carbonatoms represented by any one of R₁ to R₈ is a group represented as —OZ,and Z is selected from the substituted or unsubstituted alkyl groupseach having 1 to 50 carbon atoms represented by R₁ to R₈.

Examples of the substituted or unsubstituted aralkyl group having 7 to50 ring-forming carbon atoms (the aryl portion having 6 to 50 carbonatoms and the alkyl portion having 1 to 50 carbon atoms) as thesubstituents represented by any one of R₁ to R₈ include a benzyl group,a 1-phenylethyl group, a 2-phenylethyl group, a 1-phenylisopropyl group,a 2-phenylisopropyl group, a phenyl-t-butyl group, an α-naphthylmethylgroup, a 1-α-naphthylethyl group, a 2-α-naphthylethyl group, a1-α-naphthylisopropyl group, a 2-α-naphthylisopropyl group, aβ-naphthylmethyl group, a 1-β-naphthylethyl group, a 2-β-naphthylethylgroup, a 1-β-naphthylisopropyl group, a 2-β-naphthylisopropyl group, a1-pyrrolylmethyl group, a 2-(1-pyrrolyl)ethyl group, a p-methylbenzylgroup, an m-methylbenzyl group, an o-methylbenzyl group, ap-chlorobenzyl group, an m-chlorobenzyl group, an o-chlorobenzyl group,a p-bromobenzyl group, an m-bromobenzyl group, an o-bromobenzyl group, ap-iodobenzyl group, an m-iodobenzyl group, an o-iodobenzyl group, ap-hydroxybenzyl group, an m-hydroxybenzyl group, an o-hydroxybenzylgroup, a p-aminobenzyl group, an m-aminobenzyl group, an o-aminobenzylgroup, a p-nitrobenzyl group, an m-nitrobenzyl group, an o-nitrobenzylgroup, a p-cyanobenzyl group, an m-cyanobenzyl group, an o-cyanobenzylgroup, a 1-hydroxy-2-phenylisopropyl group, and a1-chloro-2-phenylisopropyl group.

The substituted or unsubstituted aryloxy group having 6 to 50ring-forming carbon atoms and the substituted or unsubstituted arylthiogroup having 6 to 50 ring-forming carbon atoms each represented by anyone of R₁ to R₈ are represented as —OY and —SY, respectively. Each Y isselected from the substituted or unsubstituted aryl groups having 6 to50 atoms represented by any one of R₁ to R₈.

The substituted or unsubstituted alkoxycarbonyl group having 1 to 50carbon atoms represented by any one of R₁ to R₈ is represented as —COOZZ is selected from the substituted or unsubstituted alkyl groups having1 to 50 carbonyl atoms represented by any one of R₁ to R₈.

Examples of the substituted silyl group represented by any one of R₁ toR₈ include a trimethylsilyl group, a triethylsilyl group, at-butyldimethylsilyl group, a vinyldimethylsilyl group, apropyldimethylsilyl group, and a triphenylsilyl group.

Examples of the halogen atom represented by any one of R₁ to R₈ includefluorine, chlorine, bromine, and iodine.

The substituent on an aromatic ring represented by any one of R₁ to R₈and/or A₁ and A₂ may be further substituted by a halogen atom, ahydroxyl group, a nitro group, a cyano group, an alkyl group, an arylgroup, a cycloalkyl group, an alkoxy group, an aromatic heterocyclicgroup, an aralkyl group, an aryloxy group, an arylthio group, analkoxycarbonyl group, a carboxyl group, or the like.

In the general formula (i), A₁ and A₂ preferably represent differentgroups.

The anthracene derivative represented by the general formula (i) ispreferably a compound having a structure represented by the followinggeneral formula (i′):

(in the formula, A₁ and A₂, and R₁ to R₈ are as defined in the formula(i), provided that the substituents A₁ and A₂ at the 9- and 10-positionsof the anthracene structure are asymmetric with respect to the X-Yaxis.)

Specific examples of the anthracene derivative represented by thegeneral formula (i) to be used in the organic EL device of the presentinvention include various known anthracene derivatives such as ananthracene derivative having two anthracene skeletons in its moleculedescribed in paragraphs [0043] to [0063] of JP 2004-356033 A and acompound having one anthracene skeleton described in p. 27 and 28 of WO2005/061656 A1. Representative specific examples are shown below.

(In the formula, Ar₁₅ and Ar₁₆ each independently represent asubstituted or unsubstituted aryl group having 6 to 50 ring-formingcarbon atoms;

L₁ and L₂ each independently represent a substituted or unsubstitutedphenylene group, a substituted or unsubstituted naphthalenylene group, asubstituted or unsubstituted fluorenylene group, or a substituted orunsubstituted dibenzosilolylene group;

s represents an integer of 0 to 2, p represents an integer of 1 to 4, qrepresents an integer of 0 to 2, and r represents an integer of 0 to 4;and

L₁ or Ar₁₅ is bonded to any one of 1- to 5-positions of pyrene and L₂ orAr₁₆ is bonded to any one of 6- to 10-positions of pyrene,

provided that, when p+r is an even number, Ar₁₅, Ar₁₆, L₁, and L₂satisfy the following condition (1) or (2):

(1) Ar₁₅≠Ar₁₆ and/or L₁≠L₂ (where ≠ means that groups on both of itssides are different from each other in structure); or

(2) when Ar₁₅=Ar₁₆ and L₁=L₂,

(2-1) s≠q and/or p≠r, or

(2-2) if s=q and p=r,

-   -   (2-2-1) L₁ and L₂ are, or pyrene is, bonded to different bonding        positions on Ar₁₅ and Ar₁₆, or (2-2-2) in the case where L₁ and        L₂ are, or pyrene is, bonded to the same bonding positions on        Ar₁₅ and Ar₁₆, substitution positions of L₁ and L₂ or Ar₁₅ and        Ar₁₆ on pyrene exclude 1- and 6-positions or 2- and        7-positions.)

Specific examples of, and substituents for, the respective groupsrepresented by Ar₁₅ and Ar₁₆, and L₁ and L₂ include the same examples asthose described for the general formula (i).

Specific examples of the pyrene derivative represented by the generalformula (ii) are shown below, however, the derivative is not limited tothese exemplified compounds.

It should be noted that the number of carbon atoms or atoms of eachgroup of each of the above-mentioned general formulae (i) to (ii) is anumber excluding that of a substituent. In addition, the number ofcarbon atoms of an aralkyl group is the number of carbon atoms of anaryl portion.

An arbitrary substituent in the “substituted or unsubstituted group” ineach of the above-mentioned general formulae is, for example, asubstituted or unsubstituted aryl group having 6 to 50 ring-formingcarbon atoms, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50carbon atoms, a substituted or unsubstituted aralkyl group having 7 to50 ring-forming carbon atoms, a substituted or unsubstituted aryloxygroup having 6 to 50 ring-forming carbon atoms, a substituted orunsubstituted arylthio group having 6 to 50 ring-forming carbon atoms, asubstituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbonatoms, an amino group, a halogen atom, a cyano group, a nitro group, ahydroxyl group, or a carboxyl group.

In the present invention, the organic EL device having multiple organicthin film layers is a laminate having, for example, an (anode/holeinjecting layer/light emitting layer/cathode), (anode/light emittinglayer/electron injecting layer/cathode), or (anode/hole injectinglayer/light emitting layer/electron injecting layer/cathode) structure.

If needed, in addition to the aromatic amine derivative of the presentinvention, a known light emitting material, a doping material, a holeinjecting material, or an electron injecting material may be furtherused in combination in the multiple layers. When the organic EL devicehas a structure of the multiple organic thin film layers, a reduction inluminance or lifetime due to quenching may be prevented. If needed, alight emitting material, a doping material, a hole injecting material,and an electron injecting material may be used in combination. Using adoping material in combination, improvements in emission luminance andluminous efficiency, and red or blue light emission may also beobtained. In addition, each of the hole injecting layer, the lightemitting layer, and the electron injecting layer may be formed of alayer structure having two or more layers. At that time, in the case ofthe hole injecting layer, a layer for injecting a hole from theelectrode is referred to as a hole injecting layer, and a layer foraccepting the hole from the hole injecting layer and transporting thehole to the light emitting layer is referred to as a hole transportinglayer. In the same manner, in the case of the electron injecting layer,a layer for injecting an electron from the electrode is referred to asan electron injecting layer, and a layer for accepting the electron fromthe electron injecting layer and transporting the electron to the lightemitting layer is referred to as an electron transporting layer. Each ofthose layers is selected and used depending on factors such as theenergy level of a material, heat resistance, and adhesiveness betweenthe layer and an organic layer or a metal electrode.

Examples of a host material or a doping material other than thoserepresented by the above-mentioned general formulae (i) and (ii) whichmay be used in the light emitting layer together with the aromatic aminederivative of the present invention include: polyfused aromaticcompounds such as naphthalene, phenanthrene, rubrene, anthracene,tetracene, pyrene, perylene, chrysene, decacyclene, coronene,tetraphenylcyclopentadiene, pentaphenylcyclopentadiene, fluorene,spirofluorene, 9,10-diphenylanthracene, 9,10-bis(phenylethinyl)anthracene, and 1,4-bis(9′-ethinylanthracene)benzene and derivativesthereof; organic metal complexes such as tris (8-quinolinolato)aluminumand bis-(2-methyl-8-quinolinolato)-4-(phenylphenolato)aluminum; atriarylamine derivative; a styrylamine derivative; a stilbenederivative; a coumarin derivative; a pyrane derivative; an oxazonederivative; a benzothiazole derivative; a benzoxazole derivative; abenzimidazole derivative; a pyrazine derivative; a cinnamate derivative;a diketopyrrolopyrrole derivative; an acridone derivative; and aquinacridone derivative, but the material is not limited thereto.

A compound having an ability of transporting a hole, having a holeinjection effect from an anode and an excellent hole injection effect toa light emitting layer or a light emitting material, having an abilityof preventing the migration of an exciton generated in the lightemitting layer to an electron injecting layer or an electron injectingmaterial, and having excellent thin film-formability is preferred as ahole injecting material. Specific examples of the compound include, butare not limited to, a phthalocyanine derivative, a naphthalocyaninederivative, a porphyrin derivative, oxazole, oxadiazole, triazole,imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone,tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone,polyarylalkane, stilbene, butadiene, benzidine type triphenylamine,styrylamine type triphenylamine, diamine type triphenylamine,derivatives thereof, and polymer materials such as polyvinyl carbazole,polysilane, and a conductive polymer.

Of the hole injecting materials that may be used in the organic ELdevice of the present invention, more effective hole injecting materialsare an aromatic tertiary amine derivative and a phthalocyaninederivative.

Examples of the aromatic tertiary amine derivative include, but are notlimited to, triphenylamine, tritolylamine, tolyldiphenylamine,N,N′-diphenyl-N,N′-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine,N,N,N′,N′-(4-methylphenyl)-1,1′-phenyl-4,4′-diamine,N,N,N′,N′-(4-methylphenyl)-1,1′-biphenyl-4,4′-diamine,N,N′-diphenyl-N,N′-dinaphthyl-1,1′-biphenyl-4,4′-diamine,N,N′-(methylphenyl)-N,N′-(4-n-butylphenyl)-phenanthrene-9,10-diamine,N,N-bis(4-di-4-tolylaminophenyl)-4-phenyl-cyclohexane, and an oligomeror a polymer having one of the aromatic tertiary amine skeletons.

Examples of the phthalocyanine (Pc) derivative include, but are notlimited to, phthalocyanine derivatives such as H₂Pc, CuPc, CoPc, NiPc,ZnPc, PdPc, FePc, MnPc, ClAlPc, ClGaPc, ClInPc, ClSnPc, Cl₂SiPc,(HO)AlPc, (HO)GaPc, VOPc, TiOPc, MoOPc, and GaPc-O-GaPc, andnaphthalocyanine derivatives.

In addition, the organic EL device of the present invention ispreferably formed of a layer containing each of those aromatic tertiaryamine derivatives and/or each of phthalocyanine derivatives, such as thehole transporting layer or the hole injecting layer, between a lightemitting layer and an anode.

A compound having an ability of transporting electrons, having anelectron injection effect from a cathode and an excellent electroninjection effect to a light emitting layer or a light emitting material,having an ability of preventing the migration of an exciton generated inthe light emitting layer to the hole injecting layer, and havingexcellent thin film-formability is preferred as an electron injectingmaterial.

As specific examples of an electron injecting material, a metal complexof 8-hydroxyquinoline or of a derivative of 8-hydroxyquinoline, or anoxadiazole derivative is suitable. Specific examples of the metalcomplex of 8-hydroxyquinoline or of the derivative of 8-hydroxyquinolinethat can be used as an electron injecting material include metal chelateoxynoid compounds each containing a chelate of oxine (generally8-quinolinol or 8-hydroxyquinoline) such astris(8-quinolinolato)aluminum.

On the other hand, examples of the oxadiazole derivative includeelectron transfer compounds represented by the following generalformula:

(in the formula, Ar¹, Ar², Ar³, Ar⁵, Ar⁶, and Ar⁹ each represent asubstituted or unsubstituted aryl group and may be identical to ordifferent from each other; and Ar⁴, Ar⁷ and Ar⁸ each represent asubstituted or unsubstituted arylene group and may be identical to ordifferent from each other.)

Examples of the aryl group include a phenyl group, a biphenyl group, ananthranyl group, a perylenyl group, and a pyrenyl group. Examples of thearylene group include a phenylene group, a naphthylene group, abiphenylene group, anthranylene group, a perylenylene group, and apyrenylene group. Examples of the substituent include alkyl groups eachhaving 1 to 10 carbon atoms, alkoxy groups each having 1 to 10 carbonatoms, and a cyano group. As the electron transfer compound, compoundshaving a thin film forming property are preferred.

Specific examples of the electron transfer compounds described aboveinclude the following.

Further, materials represented by the following general formulae (A) to(F) can be used in the electron injecting material:

nitrogen-containing heterocyclic derivatives represented by the generalformulae (A) and (B):

(in the general formulae (A) and (B): A¹ to A³ each independentlyrepresent a nitrogen atom or a carbon atom, Ar¹ represents a substitutedor unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, ora substituted or unsubstituted heteroaryl group having 3 to 60ring-forming atoms, Ar² represents a hydrogen atom, a substituted orunsubstituted aryl group having 6 to 60 ring-forming carbon atoms, asubstituted or unsubstituted heteroaryl group having 3 to 60ring-forming carbon atoms, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxygroup having 1 to 20 carbon atoms, or a divalent group of any one ofthose groups provided that one of Ar′ and Ar² represents a substitutedor unsubstituted fused ring group having 10 to 60 ring-forming carbonatoms or a substituted or unsubstituted monohetero fused ring grouphaving 3 to 60 ring-forming atoms;

L¹, L², and L each independently represent a single bond, a substitutedor unsubstituted arylene group having 6 to 60 ring-forming carbon atoms,a substituted or unsubstituted heteroarylene group having 3 to 60ring-forming atoms, or a substituted or unsubstituted fluorenylenegroup;

R represents a hydrogen atom, a substituted or unsubstituted aryl grouphaving 6 to 60 ring-forming carbon atoms, a substituted or unsubstitutedheteroaryl group having 3 to 60 ring-forming atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms. n representsan integer of 0 to 5, and, when n represents 2 or more, multiple R's maybe identical to or different from each other, and multiple R groupsadjacent to each other may be bonded to each other to form a carbocyclicaliphatic ring or a carbocyclic aromatic ring);

A nitrogen-containing heterocyclic ring derivative represented by thegeneral formula (C):HAr-L-Ar¹—Ar²  (C)(in the formula, HAr represents a nitrogen-containing heterocyclic ringwhich has 3 to 40 carbon atoms and may have a substituent, L representsa single bond, an arylene group which has 6 to 60 carbon atoms and mayhave a substituent, a heteroarylene group which has 3 to 60 carbon atomsand may have a substituent, or a fluorenylene group which may have asubstituent, Ar¹ represents a divalent aromatic hydrocarbon group whichhas 6 to 60 carbon atoms and may have a substituent, and Ar² representsan aryl group which has 6 to 60 carbon atoms and may have a substituent,or a heteroaryl group which has 3 to 60 carbon atoms and may have asubstituent);

a silacyclopentadiene derivative represented by the general formula (D):

(in the formula, X and Y each independently represent a saturated orunsaturated hydrocarbon group having 1 to 6 carbon atoms, an alkoxygroup, an alkenyloxy group, an alkynyloxy group, a hydroxyl group, asubstituted or unsubstituted aryl group, or a substituted orunsubstituted heterocycle, or X and Y are bonded to each other to form astructure as a saturated or unsaturated ring; and R₁ to R₄ eachindependently represent hydrogen, a halogen atom, a substituted orunsubstituted alkyl group having 1 to 6 carbon atoms, an alkoxy group,an aryloxy group, a perfluoroalkyl group, a perfluoroalkoxy group, anamino group, an alkylcarbonyl group, an arylcarbonyl group, analkoxycarbonyl group, an aryloxycarbonyl group, an azo group, analkylcarbonyloxy group, an arylcarbonyloxy group, an alkoxycarbonyloxygroup, an aryloxycarbonyloxy group, a sulfinyl group, a sulfonyl group,a sulfanyl group, a silyl group, a carbamoyl group, an aryl group, aheterocyclic group, an alkenyl group, an alkynyl group, a nitro group, aformyl group, a nitroso group, a formyloxy group, an isocyano group, acyanate group, an isocyanate group, a thiocyanate group, anisothiocyanate group, or a cyano group, or, when two or more of R₁ to R₄are adjacent to each other, they form a structure in which substitutedor unsubstituted rings are condensed);

a borane derivative represented by the general formula (E):

(in the formula, R₁ to R₈ and Z₂ each independently represent a hydrogenatom, a saturated or unsaturated hydrocarbon group, an aromatichydrocarbon group, a heterocyclic group, a substituted amino group, asubstituted boryl group, an alkoxy group, or an aryloxy group; X, Y, andZ₁ each independently represent a saturated or unsaturated hydrocarbongroup, an aromatic hydrocarbon group, a heterocyclic group, asubstituted amino group, an alkoxy group, or an aryloxy group;substituents of Z₁ and Z₂ may be bonded to each other to form a fusedring; and n represents an integer of 1 to 3, and, when n represents 2 ormore, Z₁'s may be different from each other provided that the case wheren represents 1, X, Y, and R₂ each represent a methyl group, R₈represents a hydrogen atom or a substituted boryl group and the casewhere n represents 3 and Z₁'s each represent a methyl group areexcluded);

(in the formula, Q¹ and Q² each independently represent a ligandrepresented by the following general formula (G); and L represents ahalogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted cycloalkyl group, a substituted or unsubstituted arylgroup, a substituted or unsubstituted heterocyclic group, —OR¹ (where R¹represents a hydrogen atom, a substituted or unsubstituted alkyl group,a substituted or unsubstituted cycloalkyl group, a substituted orunsubstituted aryl group), or a substituted or unsubstitutedheterocyclic group, or a ligand represented by —O—Ga-Q³(Q⁴) (where Q³and Q⁴ are identical to Q¹ and Q², respectively).)

(In the formula, rings A¹ and A² are six-membered aryl ring structureswhich are condensed with each other and each of which may have asubstituent.)

The metal complex behaves strongly as an n-type semiconductor, and has alarge electron injecting ability. Further, generation energy uponformation of the complex is low. As a result, the metal and the ligandof the formed metal complex are bonded to each other so strongly thatthe fluorescent quantum efficiency of the complex as a light emittingmaterial improves.

Specific examples of a substituent in the rings A¹ and A² which eachform a ligand in the general formula (G) include: a halogen atom such aschlorine, bromine, iodine, or fluorine; a substituted or unsubstitutedalkyl group such as a methyl group, an ethyl group, a propyl group, abutyl group, a s-butyl group, a t-butyl group, a pentyl group, a hexylgroup, a heptyl group, an octyl group, a stearyl group, ortrichloromethyl group; a substituted or unsubstituted aryl group such asa phenyl group, a naphthyl group, a 3-methylphenyl group, a3-methoxyphenyl group, a 3-fluorophenyl group, a 3-trichloromethylphenylgroup, a 3-trifluoromethylphenyl group, or a 3-nitrophenyl group; asubstituted or unsubstituted alkoxy group such as a methoxy group, ann-butoxy group, a t-butoxy group, a trichloromethoxy group, atrifluoroethoxy group, a pentafluoropropoxy group, a2,2,3,3-tetrafluoropropoxy group, a 1,1,1,3,3,3-hexafluoro-2-propoxygroup, or a 6-(perfluoroethyl)hexyloxy group; a substituted orunsubstituted aryloxy group such as a phenoxy group, a p-nitrophenoxygroup, p-t-butylphenoxy group, a 3-fluorophenoxy group, apentafluorophenyl group, or a 3-trifluoromethylphenoxy group; asubstituted or unsubstituted alkylthio group such as a methylthio group,an ethylthio group, a t-butylthio group, a hexylthio group, an octylthiogroup, or a trifluoromethylthio group; a substituted or unsubstitutedarylthio group such as a phenylthio group, a p-nitrophenylthio group, ap-t-butylphenylthio group, a 3-fluorophenylthio group, apentafluorophenylthio group, or a 3-trifluoromethylphenylthio group; acyano group; a nitro group; an amino group; a mono-substituted ordi-substituted amino group such as a methylamino group, a diethylaminogroup, an ethylamino group, a diethylamino group, a dipropylamino group,a dibutylamino group, or a diphenylamino group; an acylamino group suchas a bis(acetoxymethyl)amino group, a bis(acetoxyethyl)amino group, abis(acetoxypropyl)amino group, or a bis(acetoxybutyl)amino group; ahydroxyl group; a siloxy group; an acyl group; a carbamoyl group such asa methylcarbamoyl group, a dimethylcarbamoyl group, an ethylcarbamoylgroup, a diethylcarbamoyl group, a propylcarbamoyl group, abutylcarbamoyl group, or a phenylcarbamoyl group; a carboxylic acidgroup; a sulfonic acid group; an imide group; a cycloalkyl group such asa cyclopentane group, or a cyclohexyl group; an aryl group such as aphenyl group, a naphthyl group, a biphenyl group, an anthranyl group, aphenanthryl group, a fluorenyl group, or a pyrenyl group; and aheterocyclic group such as a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, a triazinyl group, an indolinylgroup, a quinolinyl group, an acridinyl group, a pyrrolidinyl group, adioxanyl group, a piperidinyl group, a morpholidinyl group, apiperazinyl group, a triathinyl group, a carbazolyl group, a furanylgroup, a thiophenyl group, an oxazolyl group, an oxadiazolyl group, abenzoxazolyl group, a thiazolyl group, a thiadiazolyl group, abenzothiazolyl group, a triazolyl group, an imidazolyl group, abenzoimidazolyl group, or a puranyl group. In addition, theabove-mentioned substituents may be bonded to each other to further forma six-membered aryl ring or a heterocycle.

A preferred embodiment of the organic EL device of the present inventionincludes a device including a reducing dopant in the region of electrontransport or in the interfacial region of the cathode and the organicthin film layer. Here, the reducing dopant is defined as a substancewhich can reduce a compound having the electron-transporting property.Thus, various compounds can be used as the reducing dopant as long asthe compounds have a certain reductive property. For example, at leastone substance selected from the group consisting of alkali metals,alkaline earth metals, rare earth metals, alkali metal oxides, alkalimetal halides, alkaline earth metal oxides, alkaline earth metalhalides, rare earth metal oxides, rare earth metal halides, carbonatesof alkali metals, carbonates of alkaline earth metals, organic complexesof alkali metals, organic complexes of alkaline earth metals, andorganic complexes of rare earth metals can be suitably used.

In addition, more specifically, examples of the reducing dopantpreferably include substances having a work function of 2.9 eV or less,examples of which include at least one alkali metal selected from thegroup consisting of Na (work function: 2.36 eV), K (work function: 2.28eV), Rb (work function: 2.16 eV), and Cs (work function: 1.95 eV) and atleast one alkaline earth metal selected from the group consisting of Ca(work function: 2.9 eV), Sr (work function: 2.0 to 2.5 eV), and Ba (workfunction: 2.52 eV). Of those, at least one alkali metal selected fromthe group consisting of K, Rb, and Cs is more preferred, Rb and Cs arestill more preferred, and Cs is most preferred as the reducing dopant.Those alkali metals have high reducing ability, and the luminance of theemitted light and the life time of the organic EL device can beincreased by addition of a relatively small amount of the alkali metalinto the electron injecting zone. As the reducing dopant having a workfunction of 2.9 eV or less, combinations of two or more kinds of thealkali metals are also preferred. In particular, combinations having Cssuch as the combinations of Cs and Na, Cs and K, Cs and Rb, and Cs, Na,and K are preferred. The reducing ability can be efficiently exhibitedby the combination having Cs. The luminance of emitted light and thelife time of the organic EL device can be increased by adding thecombination having Cs into the electron injecting zone.

The present invention may further include an electron injecting layerwhich is composed of an insulating material or a semiconductor anddisposed between the cathode and the organic layer. In this case, leakof electric current can be effectively prevented, and the electroninjecting property can be improved. As the insulating material, at leastone metal compound selected from the group consisting of alkali metalchalcogenides, alkaline earth metal chalcogenides, alkali metal halides,and alkaline earth metal halides is preferred. It is preferred that theelectron injecting layer be composed of the alkali metal chalcogenide orthe like because the electron injecting property can be furtherimproved. Specifically, preferred examples of the alkali metalchalcogenide include Li₂O, K₂O, Na₂S, Na₂Se, and Na₂O. Preferredexamples of the alkaline earth metal chalcogenide include CaO, BaO, SrO,BeO, BaS, and CaSe. In addition, preferred examples of the alkali metalhalide include LiF, NaF, KF, CsF, LiCl, KCl, and NaCl. In addition,preferred examples of the alkaline earth metal halide include fluoridessuch as CaF₂, BaF₂, SrF₂, MgF₂, and BeF₂ and halides other than thefluorides.

In addition, examples of the semiconductor composing the electroninjecting layer include oxides, nitrides, and oxide nitrides of at leastone element selected from Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, Cd, Mg,Si, Ta, Sb, and Zn used alone or in combination of two or more. It ispreferred that the inorganic compound composing the electron injectinglayer form a crystallite or amorphous insulating thin film. When theelectron injecting layer is composed of the insulating thin filmdescribed above, a more uniform thin film can be formed, and defects ofpixels such as dark spots can be decreased. It should be noted thatexamples of the inorganic compound include alkali metal chalcogenides,alkaline earth metal chalcogenides, alkali metal halides, and alkalineearth metal halides which are described above.

Next, as the cathode, a material such as a metal, an alloy, a conductivecompound, or a mixture of those materials which has a small workfunction (4 eV or less) is used. Specific examples of the electrodematerial include sodium, sodium-potassium alloys, magnesium, lithium,cesium, magnesium-silver alloys, aluminum/aluminum oxide, Al/Li₂O,Al/LiO, Al/Lif, aluminum-lithium alloys, indium, and rare earth metals.

The cathode can be prepared by forming a thin film of the electrodematerial by a process such as vapor deposition and sputtering.

Here, when the light emitted from the light emitting layer is obtainedthrough the cathode, it is preferred that the cathode have atransmittance of the emitted light of more than 10%. It is alsopreferred that the sheet resistivity of the cathode be several hundredΩ/□ or less. Further, the thickness of the cathode is, in general, inthe range of 10 nm to 1 μm and preferably in the range of 50 to 200 nm.

Further, defects in pixels generally tend to be formed inorganic ELdevice due to leak and short circuit because an electric field isapplied to ultra-thin films. To prevent the formation of the defects, alayer of a thin film having an insulating property may be insertedbetween the pair of electrodes.

Examples of the material used for the insulating layer include aluminumoxide, lithium fluoride, lithium oxide, cesium fluoride, cesium oxide,magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride,aluminum nitride, titanium oxide, silicon oxide, germanium oxide,silicon nitride, boron nitride, molybdenum oxide, ruthenium oxide, andvanadium oxide. Mixtures and laminates of the materials may also beused.

In the organic EL device of the present invention, in addition to atleast one kind of aromatic amine derivative selected from the generalformula (1), at least one kind of light emitting material, dopingmaterial, hole injecting material, and electron injecting material maybe incorporated into the light emitting layers. In addition, the surfaceof the organic EL device obtained according to the present invention maybe provided with a protective layer, or the entire device may beprotected with silicone oil, a resin, or the like with a view toimproving the stability of the device against temperature, humidity, anatmosphere, or the like.

A conductive material having a work function of more than 4 eV issuitably used in the anode of the organic EL device of the presentinvention. Examples of the conductive material to be used include:carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver,gold, platinum, palladium, and alloys thereof; metal oxides such as tinoxide and indium oxide to be used in an ITO substrate and an NESAsubstrate; and further, organic conductive resins such as polythiopheneand polypyrrole. A conductive substance having a work function of lessthan 4 eV is suitably used in the cathode. Examples of the conductivesubstance to be used include, but are not limited to, magnesium,calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese,aluminum, lithium fluoride, and alloys thereof. Representative examplesof the alloys include, but are not limited to, a magnesium/silver alloy,a magnesium/indium alloy, and a lithium/aluminum alloy. A ratio betweenthe components of the alloy is controlled depending on, for example, thetemperature of a deposition source, an atmosphere, and the degree ofvacuum, and is selected appropriately. Each of the anode and the cathodemay be formed in a layer structure having two or more layers if needed.

It is desirable that at least one surface of the organic EL device ofthe present invention be sufficiently transparent in the emissionwavelength region of the device so that the device may efficiently emitlight, A substrate is also desirably transparent. A transparentelectrode is formed by using any one of the above-mentioned conductivematerials, and is set by a method such as deposition or sputtering insuch a manner that desired translucency is secured. The lighttransmittance of an electrode on a light emitting surface is desirably10% or more. The substrate is not limited as long as it has mechanicalstrength, thermal strength, and transparency. Examples of the substrateinclude a glass substrate and a transparent resin film. Examples of thetransparent resin film include polyethylene, an ethylene-vinyl acetatecopolymer, an ethylene-vinyl alcohol copolymer, polypropylene,polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinylalcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone,polyether sulfone, a tetrafluoroethylene-perfluoroalkyl vinyl ethercopolymer, polyvinyl fluoride, a tetrafluoroethylene-ethylene copolymer,a tetrafluoroethylene-hexafluoropropylene copolymer,polychlorotrifluoroethylene, polyvinylidene fluoride, polyester,polycarbonate, polyurethane, polyimide, polyether imide, polyimide, andpolypropylene.

Any one of dry film forming methods such as vacuum deposition,sputtering, plasma, and ion plating, and wet film forming methods suchas spin coating, dipping, and flow coating is applicable to theformation of each layer of the organic EL device according to thepresent invention. The thickness of each layer is not particularlylimited, but must beset to an appropriate thickness. An excessivelylarge thickness requires an increased applied voltage for obtainingcertain optical output, resulting in poor efficiency. An excessivelysmall thickness causes a pin hole or the like, with the result thatsufficient emission luminance cannot be obtained even when an electricfield is applied. In general, the thickness is in the range ofpreferably 5 nm to 10 μm, or more preferably 10 nm to 0.2 μm.

In the case of a wet film forming method, a material of which each layeris formed is dissolved or dispersed into an appropriate solvent such asethanol, chloroform, tetrahydrofuran, or dioxane, to thereby form a thinfilm. At that time, any one of the solvents may be used. In addition, anappropriate resin or additive may be used in each of the organic thinfilm layers for, for example, improving film formability or preventing apin hole in the film. Examples of an available resin include: insulatingresins such as polystyrene, polycarbonate, polyallylate, polyester,polyamide, polyurethane, polysulfone, polymethyl methacrylate,polymethyl acrylate, and cellulose, and copolymers thereof;photoconductive resins such as poly-N-vinylcarbazole and polysilane; andconductive resins such as polythiophene and polypyrrole. In addition,examples of, the additive include an antioxidant, a UV absorber, and aplasticizer.

The organic EL device of the present invention may find use inapplications including a flat luminous body such as the flat paneldisplay of a wall hanging television, a light source for the backlight,meters, or the like of a copying machine, a printer, or a liquid crystaldisplay, a display panel, and a signal lamp. In addition, the materialof the present invention may be used in not only the field of an organicEL device but also the fields of an electrophotographic photosensitivemember, a photoelectric conversion device, a solar cell, an imagesensor, and the like.

EXAMPLES

Next, the present invention is described in more detail by way ofexamples.

Synthesis Example 1 (Synthesis of Compound D1) (1) Synthesis ofN-(2-dibenzofuranyl)acetamide

In a stream of argon, 4.25 g of acetamide, 17.8 g of2-bromodibenzofuran, 0.7 g of copper iodide, 0.63 g ofN,N′-dimethylethylenediamine, 39.7 g of potassium carbonate, and xylenewere subjected to a reaction under reflux for 12 hours.

After having been cooled, the resultant was filtrated, and then cleanwater and toluene were added to the filtrate so that an organic layermight be separated. The organic layer was washed with clean water threetimes, and was then concentrated under reduced pressure. As a result,19.9 g of a yellowish white solid were obtained. The solid wasidentified as N-(2-dibenzofuranyl)acetamide by field desorption massspectrometry (FD-MS).

(2) Synthesis of N-(2-dibenzofuranyl)-N-phenylacetamide

Synthesis was performed in the same manner as in the synthesis ofN-(2-dibenzofuranyl)acetamide in the section (1) except thatN-(2-dibenzofuranyl)acetamide was used instead of acetamide, andbromobenzene was used instead of 2-bromodibenzofuran. The resultant wasidentified as N-(2-dibenzofuranyl)-N-phenylacetamide by field desorptionmass spectrometry (FD-MS).

(3) Synthesis of N-(2-dibenzofuranyl)-N-phenylamine

First, 7.9 g of N-(2-dibenzofuranyl)-N-phenylacetamide, 8.8 g ofpotassium hydroxide, 10 mL of clean water, 25 mL of ethanol, and 50 mLof toluene were loaded, and then the mixture was subjected to a reactionunder reflux for 7 hours.

After the resultant had been cooled, clean water was added to theresultant, and then the mixture was filtrated. Clean water and toluenewere added to the filtrate so that an organic layer might be separated.The organic layer was washed with clean water three times, and was thenconcentrated. The resultant coarse product was recrystallized withtoluene and ethanol, and then the resultant solid was dried underreduced pressure. As a result, 4.2 g of a white solid were obtained. Thesolid was identified as N-(2-dibenzofuranyl)-N-phenylamine by FD-MS.

(4) Synthesis of Compound D1

In a stream of argon, 4.2 g of N-(2-dibenzofuranyl)-N-phenylamine, 2.8 gof 6,12-dibromochrysene, 186 mg of Pd₂(dba)₃, 259 mg of P(t-Bu)₃, 4.3 gof t-butoxysodium, and 20 mL of toluene were loaded, and then themixture was subjected to a reaction at 80° C. for 4 hours.

After the resultant had been cooled, toluene was added to the resultant,and then the mixture was subjected to celite filtration, After that, thefiltrate was concentrated, and then the resultant concentrate waspurified by silica gel chromatography (hexane:dichloromethane=6:1). Theresultant solid was washed with n-hexane, and was then dried underreduced pressure. As a result, 3.2 g of a yellowish white solid wereobtained. The solid was identified as Compound D1 by FD-MS.

Synthesis Example 2 (Synthesis of Compound D21)

Synthesis was performed in the same manner as in the foregoing exceptthat 9,10-dibromoanthracene was used instead of 6,12-dibromochrysene inthe section (4) of Synthesis Example 1. The resultant was identified asCompound D21 by FD-MS.

Synthesis Example 3 (Synthesis of Compound D57) (1) Synthesis ofN,N-(di-2-dibenzofuranyl)acetamide

In a stream of argon, 4.25 q of acetamide, 37.0 g of2-bromodibenzofuran, 0.7 g of copper iodide, 0.63 g ofN,N′-dimethylethylenediamine, 39.7 g of potassium carbonate, and xylenewere subjected to a reaction under reflux for 12 hours.

After having been cooled, the resultant was filtrated, and then cleanwater and toluene were added to the filtrate so that an organic layermight be separated. The organic layer was washed with clean water threetimes, and was then concentrated under reduced pressure. As a result,22.5 g of a white solid were obtained. The solid was identified asN,N-(di-2-dibenzofuranyl)acetamide by FD-MS.

(2) Synthesis of N,N-(di-2-dibenzofuranyl)amine

Synthesis was performed in the same manner as in the section (3) ofSynthesis Example 1 except that N,N-(di-2-dibenzofuranyl) acetamidesynthesized in the section (1) was used instead ofN-(2-dibenzofuranyl)-N-phenylacetamide in the synthesis ofN-(2-dibenzofuranyl)-N-phenylamine. The resultant was identified asN,N-(di-2-dibenzofuranyl)amine by FD-MS.

(3) Synthesis of Compound D57

Synthesis was performed in the same manner as in the section (4) ofSynthesis Example 1 except that 1,5-di-t-butyl-3,7-dibromonaphthalenewas used instead of 6,12-dibromochrysene, andN,N-(di-2-dibenzofuranyl)amine was used instead ofN-(2-dibenzofuranyl)-N-phenylamine. The resultant was identified asCompound D57 by FD-MS.

Example 1

A transparent electrode formed of indium tin oxide and having athickness of 120 nm was provided on a glass substrate measuring 25 mm by75 mm by 1.1 mm. The glass substrate was subjected to UV/ozoneirradiation, and washed. After that, the substrate was placed a vacuumdeposition apparatus.

First,N′,N″-bis[4-(diphenylamino)-phenyl]-N′,N″-diphenylbiphenyl-4,4′-diaminewas deposited from the vapor so as to serve as a hole injecting layerhaving a thickness of 60 nm. After that,N,N,N′,N′-tetrakis(4-biphenyl)-4,4′-benzidine was deposited from thevapor onto the layer so as to serve as a hole transporting layer havinga thickness of 20 nm. Next,10,10′-bis[1,1′,4′,1″]terphenyl-2-yl-9,9′-bianthracenyl (BTBAN) as ahost material and Compound D1 described above as a doping material weresimultaneously deposited from the vapor at a weight ratio of 40:2 sothat a light emitting layer having a thickness of 40 nm might be formed.

Next, tris (8-hydroxyquinolinato)aluminum was deposited from the vaporonto the light emitting layer so as to serve as an electron injectinglayer having a thickness of 20 nm. Then, lithium fluoride was depositedfrom the vapor so as to have a thickness of 1 nm, and then aluminum wasdeposited from the vapor so as to have a thickness of 150 nm. Thealuminum/lithium fluoride functions as a cathode. Thus, an organic ELdevice was produced.

The resultant device was then subjected to an energization test. As aresult, blue light emission having a current efficiency of 6.1 cd/A andan emission luminance of 600 cd/m² (luminous maximum wavelength: 458 nm)was obtained at a voltage of 6.4 V and a current density of 10 mA/cm². Acontinuous DC energization test was performed at an initial luminance of500 cd/m². As a result, a half lifetime was 10,000 hours.

Example 2

An organic EL device was produced in the same manner as in Example 1except that Compound D50 was used instead of Compound D1 as a dopingmaterial.

The resultant device was subjected to an energization test. As a result,green light emission having a current efficiency of 18.1 cd/A and anemission luminance of 1800 cd/m² (luminous maximum wavelength: 520 nm)was obtained at a voltage of 6.0 V and a current density of 10 mA/cm². Acontinuous DC energization test was performed at an initial luminance of500 cd/m². As a result, a half lifetime was 35,000 hours.

Example 3

An organic EL device was produced in the same manner as in Example 1except that Compound D22 was used instead of Compound D1 as a dopingmaterial.

The resultant device was subjected to an energization test. As a result,blue light emission having a current efficiency of 7.5 cd/A and anemission luminance of 750 cd/m² (luminous maximum wavelength: 466 nm)was obtained at a voltage of 6.2 V and a current density of 10 mA/cm². Acontinuous DC energization test was performed at an initial luminance of500 cd/m². As a result, a half lifetime was 14,000 hours.

Comparative Example 1

An organic EL device was produced in the same manner as in Example 1except that 6,12-bis(diphenylamino)chrysene was used instead of CompoundD1 as a doping material.

The resultant device was subjected to an energization test. As a result,blue light emission having a current efficiency of 3.5 cd/A and anemission luminance of 311 cd/m² (luminous maximum wavelength: 451 nm)was obtained at a voltage of 6.2 V and a current density of 10 mA/cm². Acontinuous DC energization test was performed at an initial luminance of500 cd/m². As a result, a half lifetime was as short as 1000 hours.

INDUSTRIAL APPLICABILITY

As specifically described above, the organic EL device using thearomatic amine derivative of the present invention has high luminousefficiency, hardly deteriorates even after long-term use, and has a longlifetime. Therefore, the organic EL device is useful as a flat luminousbody of a wall hanging television or a light source for backlight or thelike of a display.

The invention claimed is:
 1. An organic electroluminescence device,comprising an organic thin film layer formed of one or more layerscomprising a light emitting layer and interposed between a cathode andan anode, wherein the light emitting layer comprises a light emittingmaterial that is an aromatic amine derivative represented by formula (1)or a doping material that is an aromatic amine derivative represented byformula (1):

wherein: Ar₀ represents a substituted or unsubstituted pyrenylene group,wherein the optional substituent is an unsubstituted group selected froman aryl group having 6 to 50 ring carbon atoms and an alkyl group having1 to 50 carbon atoms; Ar₂, and Ar₄ each independently represent asubstituted or unsubstituted phenyl group or a substituted orunsubstituted naphthyl group; and Ar₁ and Ar₃ each independentlyrepresent a group represented by formula (3):

wherein: n represents 0: 1 represents 0 or 1; X represents oxygen orsulfur; Ar represents a substituted or unsubstituted arylene grouphaving 6 to 60 ring-forming carbon atoms; and R represents anunsubstituted group selected from a methyl group, an ethyl group, an-propyl group, an isopropyl group, a n-butyl group, a t-butyl group, aphenyl group, and a naphthyl group; and wherein: —NAr₁Ar₂ and —NAr₃Ar₄are bonded to 1- and 6-positions of the pyrenylene group, respectivelyor —NAr₁Ar₂ and —NAr₃Ar₄ are bonded to 2- and 7-positions of thepyrenylene group, respectively.
 2. The organic electroluminescencedevice according to claim 1, wherein: Ar₀ represents an unsubstitutedpyrenylene group; and Ar₂ and Ar₄ each independently represent anunsubstituted phenyl group or an unsubstituted naphthyl group.
 3. Theorganic electroluminescence device according to claim 1, wherein thesubstitute of Ar₀ is an unsubstituted group selected from a methylgroup, an ethyl group, a n-propyl group, an isopropyl group, a n-butylgroup, a t-butyl group, a phenyl group, and a naphthyl group.
 4. Theorganic electroluminescence device according to claim 1, wherein Xrepresents oxygen.
 5. The organic electroluminescence device accordingto claim 1, wherein X represents sulfur.
 6. The organicelectroluminescence device according to claim 1, wherein 1 represents 0.7. The organic electroluminescence device according to claim 1, wherein1 represents
 1. 8. The organic electroluminescence device according toclaim 2, wherein X represents oxygen.
 9. The organic electroluminescencedevice according to claim 2, wherein X represents sulfur.
 10. Theorganic electroluminescence device according to claim 2, wherein 1represents
 0. 11. The organic electroluminescence device according toclaim 2, wherein 1 represents
 1. 12. The organic electroluminescencedevice according to claim 8, wherein 1 represents
 0. 13. The organicelectroluminescence device according to claim 8, wherein 1 represents 1.14. The organic electroluminescence device according to claim 9, wherein1 represents
 0. 15. The organic electroluminescence device according toclaim 9, wherein 1 represents
 1. 16. The organic electroluminescencedevice according to claim 3, wherein X represents oxygen.
 17. Theorganic electroluminescence device according to claim 3, wherein Xrepresents sulfur.
 18. The organic electroluminescence device accordingto claim 3, wherein 1 represents
 0. 19. The organic electroluminescencedevice according to claim 3, wherein 1 represents
 1. 20. The organicelectroluminescence device according to claim 16, wherein 1 represents0.
 21. The organic electroluminescence device according to claim 16,wherein 1 represents
 1. 22. The organic electroluminescence deviceaccording to claim 17, wherein 1 represents
 0. 23. The organicelectroluminescence device according to claim 17, wherein 1represents
 1. 24. The organic electroluminescence device according toclaim 1, a bonding position of the group represented by formula (3) ispresent at a 2- or 4-position.
 25. The organic electroluminescencedevice according to claim 1, wherein the light emitting layer comprisesthe light emitting material and the light emitting material is thearomatic amine derivative.
 26. The organic electroluminescence deviceaccording to claim 25, wherein the light emitting material is a bluelight emitting material.
 27. The organic electroluminescence deviceaccording to claim 25, wherein the light emitting material is a greenlight emitting material.
 28. The organic electroluminescence deviceaccording to claim 1, wherein the light emitting layer comprises thedoping material and the doping material is the aromatic aminederivative.
 29. The organic electroluminescence device according toclaim 28, wherein the light emitting layer comprises a host material andthe host material is an anthracene derivative represented by formula(i):

wherein: A₁ and A₂ each independently represent a group derived from asubstituted or unsubstituted aromatic ring having 6 to 20 ring-formingcarbon atoms; and R₁ to R₈ each independently represent a group selectedfrom a hydrogen atom, a substituted or unsubstituted aryl group having 6to 50 ring-forming carbon atoms, a substituted or unsubstitutedheteroaryl group having 4 to 50 ring-forming atoms, a substituted orunsubstituted alkyl group having 1 to 50 carbon atoms, a substituted orunsubstituted cycloalkyl group having 3 to 50 ring-forming carbon atoms,a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms,a substituted or unsubstituted aralkyl group having 7 to 50 ring-formingcarbon atoms, a substituted or unsubstituted aryloxy group having 6 to50 ring-forming carbon atoms, a substituted or unsubstituted arylthiogroup having 6 to 50 ring-forming carbon atoms, a substituted orunsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, asubstituted or unsubstituted silyl group, a carboxyl group, a halogenatom, a cyano group, a nitro group, and a hydroxyl group.
 30. Theorganic electroluminescence device according to claim 29, wherein A₁ andA₂ in formula (i) are different from each other.
 31. The organicelectroluminescence device according to claim 28, wherein the lightemitting layer comprises a host material and the host material is apyrene derivative represented by formula (ii):

where: Ar₁₅ and Ar₁₆ each independently represent a substituted orunsubstituted aryl group having 6 to 50 ring-forming carbon atoms; L₁and L₂ each independently represent a substituted or unsubstitutedphenylene group, a substituted or unsubstituted naphthalenylene group, asubstituted or unsubstituted fluorenylene group, or a substituted orunsubstituted dibenzosilolylene group; s represents an integer of 0 to2, p represents an integer of 1 to 4, q represents an integer of 0 to 2,and r represents an integer of 0 to 4; and L₁ or Ar₁₅ is bonded to anyone of 1- to 5-positions of pyrene and L₂ or Ar₁₆ is bonded to any oneof 6- to 10-positions of pyrene, provided that, when p+r is an evennumber, Ar₁₅, Ar₁₆, L₁, and L₂ satisfy the following condition (1) or(2): (1) Ar₁₅#Ar₁₆ and/or L₁#L₂ where # means that groups on both of itssides are different from each other in structure; or (2) when Ar₁₅=Ar₁₆and L₁=L₂, (2-1) s#q and/or p#r, or (2-2) if s=q and p=r, (2-2-1) L₁ andL₂ are, or pyrene is, bonded to different bonding positions on Ar₁₅ andAr₁₆, or (2-2-2) in the case where L₁ and L₂ are, or pyrene is, bondedto the same bonding positions on Ar₁₅ and Ar₁₆, substitution positionsof L₁ and L₂ or Ar₁₅ and Ar₁₆ on pyrene exclude 1- and 6-positions or 2-and 7-positions.